Hello,

> 	I think the cooling fan is controlled by logic attached to the PMU. I 
> believe it gets the thermal data from the CPU thermal sensor on pre 
> uni-north systems via the pmu as well. pmu99 and the uni-n i2c stuff 
> isn't too familiar to me. There must be a way to kick the fans onto 
> high speed for testing because my Wallstreet does it when you do a PMU 
> reset.

In my iBook it's apparently controlled by an ADT7467 which also monitors temperatures, core voltage and so on. It has a few registers to control at which temperature it should turn the fan on or off, so it even works without MacOS :)

Just hacked a driver together to talk to it - temperatures work, not sure about fan speed because it didn't spin up yet and core voltage is wrong - either I did something wrong (likely) or OF didn't activate this sensor ( not quite as likely but possible ).

have fun
Michael